The Social Science Statistics blog (new to me, but it’s been around for a while) has a good writeup of a 2002 study by Dan Ariely and Klaus Wertenbroch which systematically examines the effectiveness of deadlines in preventing procrastination:
They randomized participants into three categories: three evenly-spaced deadlines every 7 days; an end-deadline after 21 days; or a self-imposed schedule of deadlines within a three week period.
Which one would you select if you could? Maybe the end-deadline because it gives you the most flexibility in arranging the work (similar to a final exam or submitting your dissertation all at once)? Ariely and Wertenbroch found that the end-deadline does the worst both in terms of finding errors and submitting on time. Participants with evenly-spaced deadline did best. But that group also liked the task the least, maybe because they had several unpleasant episodes of reading silly texts, or because they spent more time than the other groups.
To me the most interesting result of the study is that self-imposed deadlines don’t appear to help procrastinators [update: they do help, just not as much as external deadlines]: they need rigid, externally-imposed deadlines in order to get the job done. And as Sebastian Bauhoff points out in his summary, even then they don’t like it.
[update: added a figure below]
Here’s a summary of the results for a proofreading task: